A. Field of Invention
The present invention is directed generally to an electrical conductor for conducting electrical energy to a load, and more particularly to a cable with a feature for establishing electrical communication with ground.
B. Description of the Related Art
Traditionally, the electrical connection between tractors and trailers that navigate public roads are grounded through the trailer kingpin and fifth-wheel hitch assembly. These trailer features are exposed to weather that can cause corrosion of the hitch assembly, as well as grease, dirt and debris that can each form a significant impedance the flow of electric current through a circuit. Such an impedance leads to low voltage or faulty ground-wire connections that frequently cause failure in trailer accessories such as battery chargers, mechanized liftgates and lights. A failure of this nature can require roadside assistance and extended periods of downtime for the trailer, each of which are costly for fleet managers and owner/operators.
To avoid the problems associated with grounding through a fifth-wheel hitch assembly, others have attempted to establish an electrical connection to ground with a seven-way plug. The seven-way plug includes seven conductors that cooperate with a compatible receptacle on the trailer and/or the tractor to establish an electrical connection therebetween. One of the seven conductors is dedicated as a ground conductor that is coupled to a grounded cable. The grounded cable typically has a larger cross-sectional diameter than the cable coupled to each of the other 6 conductors in the plug. Despite the enlarged grounded cable, however, the electrical connection to ground is inadequate for the electrical power requirements of common features on trailers such as liftgates.
Attempts have been made to implement large-diameter grounding cables to satisfy the grounding requirements of power-intensive features found on trailers. Large-diameter cables, however, are typically rigid, and make the electrical conductor between a tractor and a trailer bulky and rigid when combined with the six other cables coupled to the remaining conductors of the seven-way plug. As the position of the trailer relative to the tractor changes, such as when the tractor and trailer turn a corner, the rigid electrical conductor can cause the plug to be forced from the tractor or the trailer, thereby disrupting the electrical connection.
Accordingly, there is a need in the art for a cable to establish a suitably-grounded electrical connection between a source receptacle provided to a tractor and a load receptacle provided to a trailer. The cable can also optionally compensate for changes in the position of the trailer relative to the tractor.